Casters are commonly used as wheels on a variety of appliances, devices, and tools to allow the appliance or tool to be moved about a variety of places. Many structures, such as shopping carts, chairs, tables, and various other types of machinery are mounted on caster wheels for ease of motion. The caster wheels of such devices are often equipped with locks or brakes, often in the form of a small pedal or lever. When the lever of a brake pedal is depressed, it engages with the caster wheel, thus preventing the wheel from turning and allowing the caster wheel to be locked in place.
While casters are highly desirable in that they can pivot about an axis point other than the axle of the wheel, one problem with casters is that they tend to be relatively small and can easily be interfered with by bolts, nuts and other debris which may have fallen on the floor. If the caster is suddenly engaged with such materials, the appliance, equipment, or device which is carried by the caster can tip over. When such a caster is used in a crowded work environment that includes cables, cords and hoses lying on the ground, the caster wheels often contact the objects on the floor. Because the diameter of the hoses or cables may be fairly large relative to the diameter of the caster wheel, the objects on the floor may prevent the continued rolling or turning movement of the snagged caster wheel, which prevents proper operation of the equipment. Additionally, even when the caster wheels are forced over such hoses or cables, it is possible that the contact between the caster wheels and the hoses or cables may result in damage, wear, or possible disconnection of the cables or hoses.
Alternatively, the obstruction may wedge between the caster and the floor and may be dragged some distance thereby damaging the floor. Thus, for example, a nut or bolt may leave large scratches in the floor or may snag or otherwise damage carpet.
The use of caster skirts is not new, and a number of wheel guards or shrouds have been developed. For example U.S. Pat. No. 5,615,450 shows a caster skirt which fits about the caster to prevent contact with nuts, bolts, screws, and the like.
Such caster skirts have drawbacks and disadvantages. For example, one problem with the embodiments shown in the '450 patent is that the caster skirt interferes with a locking mechanism which can be used to lock the caster in a given position when movement of the appliance or tool is not desired. Further, traditional caster skirts—which surround the wheel or are shaped as a yoke around the wheel—are vulnerable to certain types of debris such as string, which can become wrapped around both the caster portion and the skirt portion, thus jamming the caster wheel or preventing it from pivoting correctly until the string is cut free.
Thus there is a need for a caster skirt which does not interfere with the action of a locking mechanism or break, and which also provides some resistance to tangling by debris such as string, fine wire, or twine. Further, it is advantageous if the sweeping material of the skirt can be readily replaced or removed. Finally, it is advantageous if the caster skirt cannot rotate downwards, where the skirt itself may catch against the floor, causing the caster to snag or seize.
The various embodiments described by the present specification are described in greater detail below.